210231221 has 4 divisors (see below), whose sum is σ = 210277452. Its totient is φ = 210184992.

The previous prime is 210231211. The next prime is 210231223. The reversal of 210231221 is 122132012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 55502500 + 154728721 = 7450^2 + 12439^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-210231221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 210231196 and 210231205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210231223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15446 + ... + 25671.

It is an arithmetic number, because the mean of its divisors is an integer number (52569363).

Almost surely, 2^210231221 is an apocalyptic number.

It is an amenable number.

210231221 is a deficient number, since it is larger than the sum of its proper divisors (46231).

210231221 is an equidigital number, since it uses as much as digits as its factorization.

210231221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46230.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 210231221 is about 14499.3524338158. The cubic root of 210231221 is about 594.6102675735.

Adding to 210231221 its reverse (122132012), we get a palindrome (332363233).

The spelling of 210231221 in words is "two hundred ten million, two hundred thirty-one thousand, two hundred twenty-one".